For last Christmas (2014) my brother Winny gave me a nice present: a Waeco PerfectCoffee MC01 coffee maker, powered by just 12V. I had not yet dared to try it out, because of the anticipated power needed. The 12V version requires 170W (as of the manual; the website states actually 180W), which translates to 15A current. But now with the updated wiring which supports up to 30A I was finally in a position to give it a try.
So I filled in the coffee and the water and started the coffee maker. The voltage of the consumer circuit which had been at a healthy 12.9V dropped instantly to 10.8V. So I decided to start the car engine to give some power support with the alternator. Then the voltage went up to 12.0V in the consumer circuit. On the solar panel controller I could see that the battery voltage at that point actually was even much higher: at 13.2V because of the alternator, while the consumer circuit still was at 12V. The current draw of the coffee maker was then 13A.
This is because of the voltage regulator in the solar panel control which limits the voltage of the consumer circuits. Once I have my own control box ready, I will have some more clarity regarding the various voltages and the currents that flow in the electric system.
When I switched off the car engine to have the coffee maker powered only on by the battery, I did observe the battery voltage still showing a value of 11.7V, while the consumer circuit voltage was at 10.8V. The current draw then was 11A.
But in the meantime the coffee was brewing nicely.
And after about 12 minutes a cup of delicious coffee was ready. Excellent! Now I can be completely mobile and have a cup of coffee. Can surely be also made into a tea cooker. And all without the need for any gas bottle or gas cooker - GREAT!
The next test of a major appliance will be the batter-powered microwave oven - also a present from my technology-conscious brother Winny. For this one I want to have my junction box ready, so that I can see the power distribution of the required 30 or so Ampere...!